I have a cat who I think may be possessed by an evil spirit that starts manifesting itself every night past midnight. The cat runs around like crazy, attacks an older resident cat, wants to attack a new cat we acquired (who is kept behind a closed door for safety's sake), runs across our heads while we're sleep, and performs other mischief. We are actually becoming scared of him. It is also strange that he becomes very scared when I show him a rosary with the dangling crucifix. Do you think a priest could be summoned to exorcise a pet? I've never heard of pets being possessed by evil spirits, but what do you think I should do?

Yes, animals can be possessed by evil spirits, as is attested to by the Bible (e.g., Matt. 8:30-32). But I recommend that you take your cat to the veterinarian to rule out any medical or behavioral problems before doing anything else. (Ruling out medical and psychological problems is what must be done before human exorcisms, anyway). Only if there is no medical or behavioral explanation for your cat's problems, then consult with a priest to see what can be done.